Internal-combustion engine



ug., 7, i928.

' H. JUNKERS INTERNAL coMusTIoN ENGINE Filed April 9, 1927 lll lill

Patented dug.. 7, 192%.

HUGO JUNKERS, F FESS'U', GERMANY.

MTJEMAL-CUMBUSTIN ENG-FINE.

application nled April 9, wat, Serial No., 132,323, and in Germany April ld, i926.

My invention refers to internal combusn tion engines and has particular reference to engines provided with scavenging air or charging pumps, the piston ol which is coinbined with the working piston of the engine. llt is an object of my invention to improve this type ol' engine by shaping the scavenging air pump in a particular manner, whereby a number of important advantages are obtained.

'lhe use or" cylindrical pistons involves the disadvantage that a juxtaposition ol two working cylinders is rendered difficult Vby the cross-section. Un the other hand2 il the space required for two adjoining plstons is of no avail, but it is desired tor other reasons to make the pump piston large in diameter, :tor instance in order to be enabled to acco1nmodate parts of the gearing within the cross sectional area of the pump, it may happen that the cross-sectional area ol the pump pistons becomes unduly large, so that the quantity ol scavenging air delivered by the pump is excessive.. Double piston engines in which the scavenging air piston is mounted on the outer working piston and the pistons are operated by means of connecting.

rods extending laterally of the cylinder 1nvolve the further disadvantage that 1n order to secure these pistons against angular displacement special means, such as guide ledges in the wall of the cylinder must be provided.

According to the present invention the cylindrical scavenging air piston and cylinder are replaced by a cylinder and piston ol non-cylindrical cross-section, which isy so chosen that both cylinder and piston can easily be made and centered.

'llo this end the piston ol a scavenging air pump is given the sectional form ol a sector ol` a cylinder cooperating with a pump cylinder of similar section. i

ll am aware thatv scavenging air pumps having a cylinder and piston ol rectangular or elliptical cross-section have already been suggested, but in contradistinction to the present invention such cylinders and pistons cannot be manufactured without great dilliculty and the centering of the parts is rendered very dilhcult.

rlhe particular cross-section ol the cylinder sector according to the present invention can be chosen in accordance with the particu-- lar conditions ol each individualcase.

ln the drawings amazed to this specifica-fscavenging airV cylinder,

tion and forming part ther-col several modilications of an engine embodying in invention are illustrated diagrammatical y by way ol example.

ln the drawings Figs. l, 2, and 3 are cross-sections ol 'three diderent l'orms ol a cylinder and piston according to this invention. 1

Fig. l is a cross-section, drawn to a larger scale, and

Figs. 5 and 6 are axial cross-sections on the lines V-l and Vll;lll, respectively, in Fig. l, of a double piston engine according to the present invention. Y

ln the pump shown in Fig. l the cylinder 30 has circular cross-section, while the pissector bounded by two- `straight and two curved sides. '.lhe gaps between the pump piston and cylinder are lilled by plane walls 31 resting on thejnner wall of the cylinder 30 with their outer edges 32 and with extensions33 mounted on their middle lilies, and which are lixed to the cylinder wall by suitable means. lln the covers (not sho-wn) ol the spaces co'nlined between the walls 3l and the cylindrical cylinder wall 30 can be accommodated valves indicated at 37, and the free spaces 36 can be utilized lor conveying or accommodating1 the medium, such as air, delivered by the pump. Ylhe walls 3l prevent any angular displacement ol the piston.,

ln manufacturing a pump cylinder as hown in Fig. l, l prefer proceeding as lol owszv llheintermediate walls 3l being linished on their innerside, are mounted in pairs on a pattern piston exactly corresponding to l the pump piston 35, andthe o-uter edges 32 as well as t-he lree edges ol the parts 33 are turned down to the exact diameter ot' the Now the pattern piste-n, together with the parts 3l, 3l is mounted in the scavenging air cylinder, which has rst been t-urned down to the true diameter, and the parts 31, 33 are secured in place wit-hin the'cylinder, whereupon the pattern piston is withdrawn. The inserts 31,. 33 are now correctly centered Within the cylinder.

The piston 35 shown in Fig. l may be replaced by pistons such as shown in Figs. 2 and 3 and having a lai-convex and a bi-con-` cave cross-section, respectively.

ln the engine illustrated in Figs. 4-6 the .titl

4ton 35 has .the cross-section -ot a cylinder- A.

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circular parts ot the cylinder wall are merether advantage that all the space which is not vrequired by the piston can be'utlllzed for the accommodation of valves and forthe conveying of the air. Thus the cylinder according to Fig. 4 has rect-angular cross-Section and the cylindrical surfaces 4Q are produced` on t-he lathe ina single operation. to gether with the centering edge 41" (Fig.

' 5) and the abutments 42, against which are Atwo workin applied angular extensions 43 ofthe plane walls 44,0f the cylinder, screw bolts 45 serving for fixing the extensions 43 in position.

In the engine illustrated in Figs. 4-6 the pistons 50 and 51 are governed by the cen ral connecting rodl 52 and by rods 53 respectively, the

, three rods actmg on a three-throw crank .piston 55. fIhe working space of thescavenging alr pump shaft 54. On the outer working piston 51 iS mounted the scavenging air piston 55, a

cross-head 56 serving for connecting the pis-- tons to the outer ends of the lateral connecting rods 53, which are -thus enclosed to gether with the cross-head in the cross-sect1onal area covered by the scavenging air is accommodated betweenthe pump cylinder cover 57 and the pump piston 55. The suction valves 58 are f mounted in the cover 57 on both sides of the pump piston. As compared with the arrangement of these valves directly above the piston, I obtain the advantage that the end 'the engine. mounted in a face ofthe piston can come quite close to the inner face of the do not act towards increasing the height of The pressure valves 59 are plate 61 clamped between the cover 57 and the cylinder case 60 directly below the suction valves, so that the spaces 63, which are not utilized for the pump and are separated by,the walls 44, can be utilized for the conveying of thevair.y

mounted at the As shown in Fig. 6 these spaces 63 are in connection with the space lbelow the pump which is not utilized for the delivering of air may serve as receiver. While in former arrangements the pressure valves had to be accommodated lin the pis the engine was weight of the plates had to take up increased together with the piston, and the valve additional mass' forces 1n consequence of the piston movement,

I obtain the advantage that the valves. are

stationary and easily accessible, a large 'space being available for d their accommodation. However if it should prove desirable, the pressure va piston itself.

, iron) thanthe pump case,

Askilled in the art.

cover, so that the valves.

i and piston and a scavenging vairvplston 55, so that also that d -part of the der and piston ves can also l In pumps according to the present invention the intermediate walls and other insertions Which serve for reducing the original circular cross-section of the cylinder may be made of other material (for instance cast which may for instance consist of light metal. v

My invention is applicable to all kinds of internal combustion engines which require an auxiliary pump for gaseous material, independently from the particular construction of t-he'engine (whether single or double piston), from the mode of operation (whether with artificial ignition or with ignition by compression), and from the fuel (oil, combustible 4mixtures of air and vapor or gas). The pumps according to the present invention may be made single or double acting andthe original cross-section of the cylinder may also be of annular instead of full circular cross-section. Several pumps (for instance one for air and one for gas) may be combined wit-h one working cylinder.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person I'claim:- 1. Internal combustion engine comprising a substantially cylindrical working cylinder and piston and a scavenging air pump piston, said pump piston having outwardly the orm of a sector of a cylinder.

2. Internal combustion engine comprising a substantially cylindrical working cylinder and iston and a scavenging air pump pis ton Xed to Said working piston, said pump piston having outwardly the form of a sector of a cylinder.

3. Internal combustion engine comprising a substantially cylindrical working cylinder and piston andl a scavenging air pump cylinder and piston, said pump piston having outwardly the form of a sector of a cylinder, anl filling pieces inserted in said pump cyl- 1n er..

,4. Internal combustion engine comprising a. substantially cylindrical working cylinder and piston and a scavenging air pump cylinsaid' pump piston having outwardly the form of a sector of a cyliner, sald pump cylinder having a cross-section to match theform of said pumppiston.

6. Internal combustion engine comprising a substantially cylindrical working cylinder and piston and a scavenging air pump cylinder and piston, said pump piston having outwardly the form of a sector of a cylinder, said pump cylinder having a cross-section to match the form of said pump piston, and a casing surrounding said pump cylinder.

7. llnternal combustion engine comprising a substantially cylindrical working cylinder and piston and a scavenging air pump cylinder and piston, said pump piston having outwardly the form of al sector of a cylinder, said pump cylinder having a cross-section to mat-ch thc form of said pump piston, a casing surrounding said pump cylinder and a valve in said casing outside said pump cylinder.

8. Internal combustion engine comprising a substantially cylindrical Working cylinder and piston and a. scavenging air pump cylinder and piston, said pump piston having outwardly the form of a symmetrical cylinder sector, said pump cylinder having a crosssection to match the form of said cylinder, ay quadrangular casing surrounding and spaced from said cylinder and bracing means connecting the Walls of said casing and said cylinder.

9. Method of making a. scavenging air pump as claimed in claim 3, comprising mounting tivo illing pieces on the noncylindrical faces of a pattern piston having the form of the pump piston, reducing the outer surface of the combined pattern and lilling pieces to the exact cross-section of the pump cylinder, introducing the combined parts in said cylinder, securing said lling pieces in position in said cylinder and Withdrawing said pattern.

lln testimony whereof I aflix my signature.

HUGO JUNKERS. 

